In general, a triggerable bistable multivibrator is a logic device the output of which changes state, or is complemented, upon the application of, for example, a negative-going signal at its trigger input. It is well known that such a device can be constructed by cross-coupling the outputs of two dual-input NAND gates to one of their respective inputs. The other input of each gate is then coupled to a source of trigger signals. However, NAND gate logic results in an indeterminate output state when the negative-going trigger signal is applied and then removed. Under these conditions the multivibrator output condition is a function of whatever timing imbalance may be inherent in the otherwise symmetrical logic circuitry. In order to assure that the multivibrator will change state as desired upon the application of the trigger signal it has been necessary to appropriately condition the trigger inputs of the NAND gates.